Low-temperature total oxidation of methane by pore- and vacancy-engineered NiO catalysts

Designing methane combustion catalysts operated under low temperature (<400 degrees C) remains a huge challenge, especially for noble-metal-free catalytic systems. With NaCl as a crystalline scaffold, NiO catalyst with abundant oxygen vacancies and an ultra-high-specific surface area of 181 m(2) g(-1) is obtained. The mesoporous NiO exhibits outstanding CH4 combustion performance (T-90 = 370 degrees C at the weight hourly space velocity (WHSV) = 20,000 mL g(-1) h(-1)). X-ray photoelectron spectroscopy (XPS), H-2-temperature-programmed reduction (TPR), kinetic measurements, and O-18 isotope-labeling experiments together disclose the key role of surface lattice oxygen and reaction mechanism by NiO catalysts. More importantly, the excellent stability of NiO by doping La was obtained (low-temperature thermal stability: 385 degrees C, 400 h, 4 vol% H2O).

Automated summary

Designing methane combustion catalysts operated under low temperature remains a challenge. In this study, a NiO catalyst with abundant oxygen vacancies and a high-specific surface area was successfully prepared using NaCl as a crystalline scaffold. The mesoporous NiO exhibited excellent CH4 combustion performance and the key role of surface lattice oxygen and reaction mechanism were revealed by various experiments. Furthermore, doping La improved the stability of NiO.